In the field of electro-optics, solid state devices are being developed to improve existing apparatus and make possible functional achievements never before attainable. That is especially true in the field of communications where effective signal detection, among other, is a critical aspect of an efficient system.
Lasers which provide a relatively narrow radiation bandwidth are currently being developed for communications systems. The beam provided by the laser may act as the carrier and the information to be communicated may be impressed by modulation. In this respect such a system would be analogous to radio. Or the presence of the beam at a receiver, or its repetition rate, or its schedule may be significant. In this respect such a system would be analogous to radar. The systems are all electro-optic, however, and require an apparatus and technique for detecting the beam. The present invention is a novel electro-optic modulator that meets the requirement. It may also be operated as an electro-optic detector wherein the absorption edge of the semiconductor sandwich is adjusted to just include the radiation wavelength to be detected. Radiation of the wavelength will then be absorbed and detected by the present invention.